1. Field of the Invention
The present invention pertains to compositions of matter and particularly to the reaction products of certain tertiary phosphines, alkylene oxides and carboxylic acids. More particularly, the present invention concerns the use of these compounds in the preparation of rigid and flexible foams characterized by isocyanurate and/or urethane linkages.
2. Description of the Prior Art
Rigid and flexible foams characterized by isocyanurate and/or urethane linkages are known in the art. The prior art discloses methods for preparing foams by reacting an organic polyisocyanate with a polyol utilizing a catalyst. Foams are prepared by effecting such reaction in the presence of a blowing agent.
U.S. Pat. No. 4,021,381 teaches that, among other things, phosphines can be used as catalysts in the preparation of polyurethane foams. These catalysts, however, are not suitable for lower density foam preparation. U.S. Pat. No. 4,148,980 teaches that the reaction products of tertiary amines, alkylene oxides, and carboxylic acids can be used as catalysts in the preparation of rigid and flexible foams characterized by isocyanurate and/or urethane linkages. These catalysts, however, are not suitable for pour-in-place rigid foam applications because they cause the reaction to proceed too quickly.